diff --git a/src/PhpSpreadsheet/Writer/Xlsx/Style.php b/src/PhpSpreadsheet/Writer/Xlsx/Style.php
index 0261f22e56..cbc2773a8d 100644
--- a/src/PhpSpreadsheet/Writer/Xlsx/Style.php
+++ b/src/PhpSpreadsheet/Writer/Xlsx/Style.php
@@ -112,8 +112,10 @@ public function writeStyles(Spreadsheet $spreadsheet)
         $objWriter->writeAttribute('count', (string) count($spreadsheet->getCellXfCollection()));
 
         // xf
+        $alignment = new Alignment();
+        $defaultAlignHash = $alignment->getHashCode();
         foreach ($spreadsheet->getCellXfCollection() as $cellXf) {
-            $this->writeCellStyleXf($objWriter, $cellXf, $spreadsheet);
+            $this->writeCellStyleXf($objWriter, $cellXf, $spreadsheet, $defaultAlignHash);
         }
 
         $objWriter->endElement();
@@ -400,7 +402,7 @@ private function writeBorder(XMLWriter $objWriter, Borders $borders): void
     /**
      * Write Cell Style Xf.
      */
-    private function writeCellStyleXf(XMLWriter $objWriter, \PhpOffice\PhpSpreadsheet\Style\Style $style, Spreadsheet $spreadsheet): void
+    private function writeCellStyleXf(XMLWriter $objWriter, \PhpOffice\PhpSpreadsheet\Style\Style $style, Spreadsheet $spreadsheet, string $defaultAlignHash): void
     {
         // xf
         $objWriter->startElement('xf');
@@ -424,7 +426,13 @@ private function writeCellStyleXf(XMLWriter $objWriter, \PhpOffice\PhpSpreadshee
         $objWriter->writeAttribute('applyNumberFormat', ($spreadsheet->getDefaultStyle()->getNumberFormat()->getHashCode() != $style->getNumberFormat()->getHashCode()) ? '1' : '0');
         $objWriter->writeAttribute('applyFill', ($spreadsheet->getDefaultStyle()->getFill()->getHashCode() != $style->getFill()->getHashCode()) ? '1' : '0');
         $objWriter->writeAttribute('applyBorder', ($spreadsheet->getDefaultStyle()->getBorders()->getHashCode() != $style->getBorders()->getHashCode()) ? '1' : '0');
-        $applyAlignment = ($spreadsheet->getDefaultStyle()->getAlignment()->getHashCode() != $style->getAlignment()->getHashCode()) ? '1' : '0';
+        $applyAlignment = '1';
+        $defaultStyleAlignHash = $spreadsheet->getDefaultStyle()->getAlignment()->getHashCode();
+        if ($defaultStyleAlignHash === $style->getAlignment()->getHashCode()) {
+            if ($defaultStyleAlignHash === $defaultAlignHash) {
+                $applyAlignment = '0';
+            }
+        }
         $objWriter->writeAttribute('applyAlignment', $applyAlignment);
         if ($style->getProtection()->getLocked() != Protection::PROTECTION_INHERIT || $style->getProtection()->getHidden() != Protection::PROTECTION_INHERIT) {
             $objWriter->writeAttribute('applyProtection', 'true');
diff --git a/tests/PhpSpreadsheetTests/Writer/Xlsx/Issue3443Test.php b/tests/PhpSpreadsheetTests/Writer/Xlsx/Issue3443Test.php
new file mode 100644
index 0000000000..471c9ab384
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Writer/Xlsx/Issue3443Test.php
@@ -0,0 +1,98 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Writer\Xlsx;
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Style\Alignment;
+use PhpOffice\PhpSpreadsheetTests\Functional\AbstractFunctional;
+
+class Issue3443Test extends AbstractFunctional
+{
+    public function testNonDefaultAlign(): void
+    {
+        // Issue 3443 - default alignment not honored.
+        $spreadsheet = new Spreadsheet();
+        $styleArray = [
+            'alignment' => [
+                'horizontal' => Alignment::HORIZONTAL_CENTER,
+                'vertical' => Alignment::VERTICAL_CENTER,
+                'wrapText' => true,
+            ],
+            'font' => [
+                'name' => 'Courier New',
+            ],
+        ];
+        $spreadsheet->getDefaultStyle()->applyFromArray($styleArray);
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getCell('A1')->setValue(1);
+        $sheet->getCell('A2')->setValue(2);
+        $sheet->getCell('A3')->setValue(3);
+        $sheet->getStyle('A2')->getAlignment()->setHorizontal(Alignment::HORIZONTAL_LEFT);
+        $sheet->getStyle('A3')->getFont()->setName('Tahoma');
+
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, 'Xlsx');
+        $spreadsheet->disconnectWorksheets();
+        $rsheet = $reloadedSpreadsheet->getActiveSheet();
+        $expected1 = [
+            'horizontal' => 'center',
+            'indent' => 0,
+            'readOrder' => 0,
+            'shrinkToFit' => false,
+            'textRotation' => 0,
+            'vertical' => 'center',
+            'wrapText' => true,
+        ];
+        self::assertSame($expected1, $rsheet->getStyle('A1')->getAlignment()->exportArray());
+        $expected2 = $expected1;
+        $expected2['horizontal'] = 'left';
+        self::assertSame($expected2, $rsheet->getStyle('A2')->getAlignment()->exportArray());
+        self::assertSame($expected1, $rsheet->getStyle('A3')->getAlignment()->exportArray());
+        self::assertSame('Courier New', $rsheet->getStyle('A1')->getFont()->getName());
+        self::assertSame('Courier New', $rsheet->getStyle('A2')->getFont()->getName());
+        self::assertSame('Tahoma', $rsheet->getStyle('A3')->getFont()->getName());
+
+        $reloadedSpreadsheet->disconnectWorksheets();
+    }
+
+    public function testDefaultAlign(): void
+    {
+        // Issue 3443 - default alignment not honored.
+        $spreadsheet = new Spreadsheet();
+        $styleArray = [
+            'font' => [
+                'name' => 'Courier New',
+            ],
+        ];
+        $spreadsheet->getDefaultStyle()->applyFromArray($styleArray);
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getCell('A1')->setValue(1);
+        $sheet->getCell('A2')->setValue(2);
+        $sheet->getCell('A3')->setValue(3);
+        $sheet->getStyle('A2')->getAlignment()->setHorizontal(Alignment::HORIZONTAL_LEFT);
+        $sheet->getStyle('A3')->getFont()->setName('Tahoma');
+
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, 'Xlsx');
+        $spreadsheet->disconnectWorksheets();
+        $rsheet = $reloadedSpreadsheet->getActiveSheet();
+        $expected1 = [
+            'horizontal' => '',
+            'indent' => 0,
+            'readOrder' => 0,
+            'shrinkToFit' => false,
+            'textRotation' => 0,
+            'vertical' => '',
+            'wrapText' => false,
+        ];
+        self::assertSame($expected1, $rsheet->getStyle('A1')->getAlignment()->exportArray());
+        $expected2 = $expected1;
+        $expected2['horizontal'] = 'left';
+        $expected2['vertical'] = 'bottom';
+        self::assertSame($expected2, $rsheet->getStyle('A2')->getAlignment()->exportArray());
+        self::assertSame($expected1, $rsheet->getStyle('A3')->getAlignment()->exportArray());
+        self::assertSame('Courier New', $rsheet->getStyle('A1')->getFont()->getName());
+        self::assertSame('Courier New', $rsheet->getStyle('A2')->getFont()->getName());
+        self::assertSame('Tahoma', $rsheet->getStyle('A3')->getFont()->getName());
+
+        $reloadedSpreadsheet->disconnectWorksheets();
+    }
+}